Shoulder pain is a common complication of hemiplegia occurring in 70 to 84% of stroke survivors with a paralyzed upper extremity. Inferior subluxation of the glenohumeral joint is the major cause for the pain. Conventional intervention using slings often causes complications from immobilization. Electrical stimulation of the shoulder muscles has been shown effective in managing post-stroke subluxation in a few pilot studies. Existing surface stimulation systems, however, can not be widely accepted because of stimulation-induced pain, poor muscle selectivity, and difficulty in daily application of electrodes. We proposed to use a percutaneous intramuscular approach to make the stimulation less painful, more selective, and easier for daily use. A miniature, programmable stimulator has been developed in Phase I to drive a set of fine wire electrodes that are inserted into the muscles by a hypodermic needle. Preliminary clinical tests showed that the device and treatment are will accepted by the clinicians and their patients: and the intervention may be effective for the indicated use. Further development of the device and a larger scale, controlled clinical trial will be conducted during the proposed Phase II study to complete a pre-production device and to attain statistical data on the effectiveness of this new medical intervention. PROPOSED COMMERCIAL APPLICATION: The proposed stimulation system is expected to be prescribed to approximately 10 percent of the stroke survivors who have manifested shoulder subluxation or have been diagnosed with significant risk of developing shoulder subluxation. Using this estimate of patient number and assuming a unit price of $900, this product is anticipated to have annual sales of several million dollars.